Transport NI and the Rivers Agency have been accused of not doing their fair share of cleaning up litter.

The Government agencies have been blasted by charity Keep Northern Ireland Beautiful (KNIB), which says litter on roadside verges and in streams is putting off tourists and businesses and hurting our economy.

Both say they have little or no responsibility to clean up rubbish.

After a new litter report was published by the charity yesterday, chief executive Dr Ian Humphreys said: "Councils are not the only organisations with litter cleansing responsibilities - but they are the only ones working hard to fulfil them.

"In April every year we hold a Big Spring Clean, with around 90,000 volunteers taking part in 2015. A large number of those people are cleaning up roadside verges, open spaces and the banks of streams because it isn't being done by the organisations responsible for them."

Mr Humphreys said that in 2014-15, the amount being spent by councils to clean up litter across Northern Ireland topped £40m for the first time.

"£40m a year on street cleansing is an enormous cost but actually many hidden costs make the final bill far greater," he said.

"For example, studies have shown that high levels of litter correlate with increased rates of depression and other mental health problems. The result is an estimated £15m drained from already stretched NHS finances."

He said the last year had seen major milestones in the campaign against litter, with record numbers of school children receiving anti-litter education; record numbers of fixed penalties being issued for littering, and a record spend on street cleansing.

A record 4,443 fixed penalties were issued for littering in 2014-15, with 49% issued in Belfast, while less than 2% were issued in Lisburn and Castlereagh or Mid-Ulster.

The positive news was that these efforts have led to an improvement in the litter levels around the province.

The percentage of places surveyed which are deemed 'unacceptable' fell from 17% in 2014 to 12% in 2015, following three years of worsening results.

Northern Ireland also became the first country in the world to have every school registered with the eco-schools programme, which has anti-littering and respect for the environment at its core.

Environment Minister Mark H Durkan MLA said: "I welcome the findings of this report and commend Keep Northern Ireland Beautiful for the valuable work they undertake to raise awareness of local environmental quality issues, whether that is by educating our children through the eco-schools programme, promoting a cleaner environment through the Live Here, Love Here campaign, or the other initiatives in which they are involved.

"The improvements highlighted in the report are encouraging and show the value of a multi-faceted approach."

The Rivers Agency said: "Rivers Agency is the statutory drainage authority and has permissive powers in the Drainage Order (NI) 1973 to carry out maintenance of watercourses to ensure the free flow of water. This legislation does not empower the agency to remove litter unless it is causing an impediment to flow and is likely to increase flood risk. For clarity Rivers Agency does not own any rivers."

Transport NI said: "Litter picking on the public road network, including footways and verges, is the responsibility of councils in Northern Ireland. The only exception is the motorway network, which is mainly maintained by private contractors."